The display device having a low temperature polysilicon thin film field effect transistor (LTPS-TFT) array substrate has advantages including high resolution, fast response speed, high brightness, high aperture ratio, and the like. Furthermore, due to the characteristics of LTPS, it has high electron mobility.
As the LTPS-TFT array substrate develops towards the direction of high resolution, and the LTPS-TFT is also gradually made smaller and smaller, it would necessarily lead to reduction in the effective channel length in the thin film field effect transistor, thereby resulting in short-channel effects mainly including short channel that influences the threshold voltage, narrow channel effect, mobility field-related effect and carrier velocity saturation effect, hot carrier effect that influences the life of device, sub-threshold characteristic degradation, and so on.